DISTRICT SURVEY REPORT FOR SAND THOOTHUKUDI THOOTHUKUDI DISTRICT 1 District Survey Report – Thoothukudi District INDEX Chapter Content Page No. 1. Introduction. 1 2. Overview of Mining Activity in the District. 1 3. List of Sand Mining Leases in the District. 5 4. Details of Revenue received in last three years. 5 5. Details of Production of Sand in last three years. 5 Process of Deposition of Sediments in the rivers of the 6. District 6 7. General Profile of the District. 9 Land Utilisation Pattern in the District: Forest, 8. Agricultural, Horticultural, Mining etc. 14 9. Physiography of the District 15 10. Climate and Rainfall of the District. 15 11. Geology and Mineral wealth of Thoothukudi District. 17 12. Drainage system with description of main rivers 20 13. Salient Features of important Rivers and Streams 21 14. Mineral Potential 22 2 District Survey Report – Thoothukudi District DISTRICT SURVEY REPORT FOR SAND THOOTHUKUDI DISTRICT 1. Introduction: In conjunction to the Ministry of Environment, Forest and Climate Change, the Government of India Notification No.SO 141 (E) dated 15.01.2016 and SO 190 (E) dated 20.01.2016 the District Level Environment Impact Assessment Authority (DEIAA) and District Environment Appraisal Committee (DEAC) were constituted in Thoothukudi District for the grant of Environmental Clearance for category “B2” projects for quarrying of Minor Minerals. The main purpose of preparation of District Survey Report is to identify the mineral resources and develop the mining activities along with relevant current geological data of the District. The DEAC will scrutinize and screen scope of the category “B2” projects and the DEIAA will grant Environmental Clearance based on the recommendations of the DEAC for the Minor Minerals on the basis of District Survey Report. This District Mineral Survey Report is prepared on the basis of field work carried out in Thoothukudi district by the official from Geological Survey of India and Directorate of Geology and Mining, (Thoothukudi District), Govt. of Tamilnadu. 2. Overview of Mining Activity: Tamil Nadu Public Works Department, pioneer in all branch of engineering, is the custodian of Odai, Canal, Rivers and Water bodies in the State. Public Works Department creates, Maintains and protects all irrigation systems including the rivers. Periodical maintenance including desilting of the drains/river is carried out to maintain the functional efficiency including the carrying capacity of the river. But in rivers flood protection works are carried out by increasing top level of bund and protecting the sides of bund with revetment. The desilting was never carried out in river due to the cost constraints. Therefore, prolonged siltation for decades and more, the level of the floor of riverbed has increased and reduced the carrying capacity. Whenever floods and consequent damages occurred, it was resorted to increase the bund level to restore the carrying capacity of river. It was never thought of desilting the river due to the enormous cost, and there is problem in disposing the desilted sand. Consequence of this change in river regime and reduction in carrying capacity of the Thamirabarani River, the shoals in the rivers, divert the flow of water resulting in bund erosion and consequent breaches, which lead to loss of property and lives. 3 District Survey Report – Thoothukudi District Solution to the above problem is to desilt the shoals in the Thamirabarani River by expending huge amount. Alternatively, the economical solution to this problem is to mine the sand to remove the shoals. This option would yield net revenue to the state exchequer apart from making available the important construction material for infrastructure development at a reasonable price to the common people. The quarrying of sand in Government Poramboke lands and private patta lands had been entrusted to private agencies by the Revenue Department after concluding a lease agreement with them. The process was in practice up to August 2002. As per G.O.No. 46/Industries (MMC.1) Department, dated 25.09.2002, a high level committee had been constituted to conduct a survey of rivers and river beds in the state with reference to sand quarry. The high level committee concluded that, a) Even through several rules on sand mining exist, illegal quarrying of sand in out of control. Authority for regulating sand mining is vested with different organization such as, State Geology and Mining Department, Revenue Department and Public Works Departments. Hence, implementation and monitoring of rules and regulation regarding sand quarrying are not effective. The important task of sand mining therefore, should be entrusted to a SINGLE AGENCY. The Government issued an order vide G.O. Ms.No. 95, Industries (MMC.1) Department , dated. 01.10.2003 to operate sand quarries in Tamil Nadu by Public Works Department. Accordingly, Sand quarrying operations are being carried out from October 2003 in District of the Tamil Nadu. Based on the above instructions, the concerned Executive Engineers with their field staff will identify the quarry site considering the availability of sand deposits and sand humps, approach to the site, existing infrastructures, water head works, cross masonry works etc. After selecting the site, proposals will be sent to the concerned District Collectors. The sand mining activity is not carried out by the Public Works Department for the past two years in the district. 4 District Survey Report – Thoothukudi District 3.List of Sand Mining Leases in the District. Sl. Taluk/Division Village S.F.No. & River Collector’s Lease Bullock No Extent in Hects Name Proceedings Period Cart/Lorry No & Date NIL 4.Details of Revenue received in last three years. Sl. Name of the Quarry Quantity of sand Rate Per Load in Total No Quarried in Loads Rupees Royalty/Revenue in (Unit) Rupees NIL 5.Details of Production of Sand in last three years. Sl. No Name of sand Taluk Name of river Period of Quantity of sand Quarry product Quarried in Loads NIL 5 District Survey Report – Thoothukudi District 6.Process of Deposition of Sediments in the rivers of the District River sediment refers to the mixture of mineral matters which are derived from the weathering and erosion of rocks present in the river bed. Breaking down of rocks by a geological agent, here it is a river (flow of water), is called erosion. The erosion of rocks occurs in many ways. Weathering is described as disintegration and decomposition of rocks due to change in physical and chemical conditions of the rock. Sediments are derived by these natural processes. Sediments are subsequently transported by water and/or by the force of gravity acting on the sediments. Sediments become the river’s load and the river transport this loads through its course. Transportation of the sediments depends on the energy of the river. Boulders are transported by traction and are rolled along the bed of the river. Slightly smaller particles, such as pebbles and gravel are transported by saltation. This is where the load bounces along the bed of the river because the river has enough energy to lift the particles off the bed but the particles are too heavy to travel by suspension. Fine particles like clay and silt are transported in suspension; they are suspended in the water. Most of a river’s load is transported by suspension. Solution is a special method of transportation. This is where particles are dissolved into the water so only rocks that are soluble, such as limestone or chalk, can be transported in solution. Deposition occurs when forces responsible for sediment transportation are no longer sufficient to overcome the forces of gravity and friction which are creating a resistance to motion. To transport load, a river needs to have energy at the same time when a river loses energy, it is forced to deposit its load. One of the following ways, a river could lose its energy: 1. Reduction in the discharge: Reduction in discharge may be due to lack of precipitation and evaporation and abstraction by human activity. 2. Change in the river gradient: If the gradient of the river’s course flattens out, the river will deposit its load because it will be travelling a lot slower. When a river meets the sea a river will deposit its load because the gradient is generally reduced at sea level and the sea will absorb a lot of energy. 6 District Survey Report – Thoothukudi District Much of the material will be carried in suspension and loads in suspension erode the river banks by abrasion. When rivers flow over flatter land, they form large bends called meanders. As a river goes around a bend, most of the water is pushed towards the outside causing increased erosion. The river is now eroding sideways into its banks rather than downwards into its bed, a process called lateral erosion (Plate 1. A & B). On the inside of the bend, in contrast, there is much less water. The river will therefore be shallow and slow flowing. It cannot carry as much material and so sand and gravels will be deposited. This is called a point bar or slip off slope. Due to erosion on the outside of a bend and deposition on the inside, the shape of a meander will change over a period of time. Eventually deposition will block off the old meander to leave an oxbow lake. The oxbow lake will slowly dry up, only refilling after heavy rain or during a flood. In Thoothukudi District Thamirabarani River, Vaippar River, and their tributaries are draining and passing through the District. The Thamirabarani river is perennial in nature. 7 District Survey Report – Thoothukudi District Thoothukudi District River map 8 District Survey Report – Thoothukudi District 7. General Profile of the District: The etymology of the word “Thoothukudi” can be traced back to the period when the locals used to tap drinking water by digging small ponds (oothu in Tamil).